Synergistic Antibacterial Effects of Leaf Extracts of Acacia nilotica and Psidiumguajavaagainst Extended Spectrum Beta Lactamase (ESBL) Producing E. coli and Klebsiella pneumoniae

Abstract

The World Health Organization (WHO) recognizes traditional medicine, particularly plant medicine as an important alternative healthcare  delivery system for most of the world’s population. The use of plant extracts and phytochemicals both with known antimicrobial  properties is of great significance, in the past few years a number of investigations have been conducted worldwidetoprove antimicrobial  activities from medicinal plants. Hence, the combined antibacterial effectsofleaf extracts of A. nilotica and P. guajava against ESBLs- producing E. coli and K. pneumoniaewere investigated. Fresh leaves of the plants were collected, processed, and then  subjected to three different organic solvents (Methanol, Dichloromethane, and N-Hexane) with varying polarities(high, moderate and low)  and water extraction through the maceration method. The variousconcentrations of the leaf extracts of both plants were subjected to  antimicrobial susceptibilitytesting individually and in combination using agar well diffusion technique. The MIC and MBC were determined  according to standard microbiological protocols. The phytochemical analysesrevealed the presence of bioactive compounds with  exception of anthraquinone and reducing sugars in methanol leaves extracts (ALME+PLME). Methanol extracts of both plants  showed highest antibacterial activity against the isolates. The MIC of the plants part was detected at 2.5%and 5% (mg/ml) while the MBC  was detected at 5% and 10% (mg/ml). The findings provethat the plants part could be useful in new natural antimicrobial drug  development which couldserveas potential treatment for the infections caused by the test organisms.